zinc
Orazinc, Verazinc, Zinc 15, Zinc-220, Zincate, Zinca-Pak

Available forms
Available by prescription only
Capsules: 220 mg (50 mg zinc)
Injection: 10 ml (1 mg/ml), 30 ml (1 mg/ml with 0.9% benzyl alcohol), 5 ml (5 mg/ml); 10 ml (5 mg/ml)
Capsules: 220 mg (50 mg zinc)
Tablets: 66 mg (15 mg zinc), 110 mg (25 mg zinc), 200 mg (47 mg zinc)

Indications and dosages
 RDA of zinc. Infants up to age 1: 5 mg P.O.
Children ages 1 to 10: 10 mg P.O.
Boys and men age 11 and older: 15 mg P.O.
Girls and women age 11 and older: 12 mg P.O.
Pregnant women: 15 mg P.O.
Breast-feeding women (first 6 months): 19 mg P.O.
Breast-feeding women (second 6 months): 16 mg P.O.
 Metabolically stable zinc deficiency. Adults: 2.5 to 4 mg daily I.V. Add 2 mg daily for acute catabolic states.
 Stable zinc deficiency with fluid loss from the small bowel. Adults: Add 12.2 mg/L of total parenteral nutrition solution or 17.1 mg/kg of stool or ileostomy output.
 Zinc deficiency. Children younger than age 5: 100 mcg/kg daily I.V.
Premature infants: 300 mcg/kg daily I.V.
 Dietary supplementation. Adults: 25 to 50 mg P.O. daily.

Pharmacodynamics
Metabolic action: Zinc serves as a cofactor for more than 70 different enzymes. It facilitates wound healing, normal growth rates, and normal skin hydration and helps maintain the senses of taste and smell.
 Adequate zinc provides normal growth and tissue repair. In patients receiving total parenteral nutrition with low plasma levels of zinc, dermatitis has been followed by alopecia. Zinc is an integral part of many enzymes important to carbohydrate and protein mobilization of retinal-binding protein.

Pharmacokinetics
Absorption: Zinc is absorbed poorly from the GI tract; only 20% to 30% of dietary zinc is absorbed. After administration, zinc resides in muscle, bone, skin, kidneys, liver, pancreas, retina, prostate, and particularly RBCs and WBCs. Binds to plasma albumin, alpha-2 macroglobulin, and some plasma amino acids, including histidine, cysteine, threonine, glycine, and asparagine.
Distribution: Major zinc stores in skeletal muscle, skin, bone, and pancreas.
Metabolism: Zinc is a cofactor in many enzymatic reactions; it’s needed for synthesis and mobilization of retinal binding protein.
Excretion: After parenteral administration, 90% excreted in stool, urine, and sweat. After oral use, major route of excretion is secretion into duodenum and jejunum. Small amounts excreted in urine (0.3 to 0.5 mg daily) and sweat (1.5 mg daily).

Contraindications and precautions
Parenteral use of zinc is contraindicated in patients with renal failure or biliary obstruction (and requires caution in all patients); monitor zinc plasma levels frequently. Don’t exceed prescribed dosages. In patients with renal dysfunction or GI malfunction, trace metal supplements may need to be reduced, adjusted, or omitted. Hypersensitivity may result. Routine use of zinc supplementation during pregnancy isn’t recommended.
  Administering copper in the absence of zinc or administering zinc in the absence of copper may result in decreased serum levels of either element. When only one trace element is needed, it should be added separately and serum levels monitored closely. To avoid overdose, administer multiple trace elements only when clearly needed. In patients with extreme vomiting or diarrhea, large amounts of trace element replacement may be needed. Excessive intake in healthy persons may be deleterious.

Interactions
Drug-drug. Certain proteins, methylcellulose suspensions: Causes precipitation of these drugs. Avoid use together.
Fluoroquinolones, tetracyclines: Impairs antibiotic absorption. Avoid use together.
Drug-food. Dairy products: May reduce zinc absorption. Discourage use together.

Adverse reactions
CNS: restlessness.
GI: distress and irritation, nausea, vomiting with high doses, gastric ulceration, diarrhea.
Skin: rash.
Other: dehydration.

Effects on lab test results
None reported.

Overdose and treatment
Signs and symptoms of severe toxicity include hypotension, pulmonary edema, diarrhea, vomiting, jaundice, and oliguria.
 If toxicity occurs, stop drug and provide support measures.

Special considerations
• Results may not appear for 6 to 8 weeks in zinc-depleted patients.
• Zinc decreases absorption of tetracyclines and fluoroquinolones.
• Calcium supplements may confer a protective effect against zinc toxicity.
• Because of potential for infusion phlebitis and tissue irritation, an undiluted direct injection must not be administered into a peripheral vein.
• Don’t exceed prescribed dosage of oral zinc; if oral zinc is administered in single 2-g doses, emesis will occur.
• Monitor patient for severe vomiting and dehydration, which may indicate overdose.

Patient education
• Advise patient not to take zinc with dairy products, which can reduce zinc absorption.
• Advise patient that GI upset may occur after oral administration but may decrease if zinc is taken with food. Tell him to avoid foods high in calcium, phosphorus, or phytate during therapy.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use